The present invention relates to a phase shift mechanism for changing the phasing of an intake camshaft. In the last twenty years, automotive engineers and engine designers have worked primarily in the area of reduction of emission levels and fuel economy. Those in the art are aware that certain timing modifications between the engine intake and exhaust valves can reduce certain undesirable components in the engine exhaust.
Also, modern engine design has placed particular emphasis on improvement of the power output of the engine in view of the smaller engine displacement in today's automobiles. To enhance the power output, smaller engines are now more frequently equipped with turbochargers, intercoolers, multivalve heads for each cylinder and variable intake systems.
Variable valve timing is well known to the automotive engineer, and mechanisms of various configurations have been proposed and tested. The advantage of being able to vary the phasing of the intake camshaft relative to the engine crankshaft is well documented in numerous technical writings, however, the mechanisms to achieve this phasing have been complex and very expensive to mass produce. The present invention has been designed to overcome these disadvantages.